The majority of water heaters in use are of the storage type and their source of energy is either gas or electricity. Such energy sources are available from grids which are often in peak demand. Accordingly, the utility or the energy provider in extreme demand situations are forced to cut the energy source to some of their customers in order to reduce and control the load. In certain heavily populated cities like Los Angeles, Calif., for example, during summer time when the climate is hot, there is a huge demand for electricity by air conditioning devices and water heaters and the load on the grid is often at its maximum and thus requiring the utility/provider to do some load shedding depriving service sectors of electricity. Because electric water heaters are also large consumers of electricity they are rendered inoperative during load shedding period which occur during high demand times. This is an inconvenience to the consumer. It would be desirable to overcome this problem by the use of gas water heaters which do not rely on the electric grid. However, during winter months many households rely on gas heating which also results in peak demand periods for gas when electricity is now in surplus. In an attempt to overcome such problems, such utility providers offer programs where they can remotely control certain high consuming devices, such as air conditioners, space heating devices and water heaters, but such is not popular and as not proven successful.
As mentioned above, most water heaters are of the storage type and operated by electricity or gas. These sources of energy are expensive and particularly so during peak time periods. The loads created on the supply source is often too great to manage and the providers need to shed some of its load creating inconvenience to their customers. These storage type water heaters comprise a tank in which water from the supply line enters the tank at a temperature in the range of about 50 degrees F., and this varies depending on latitude and the seasons and the source of water, such as city supply or artesian well. A resistive heating element projecting in the tank or a burner disposed beneath the tank heats the water within the tank to a temperature typically in the range of from 105 to 120 degrees F. A resistive heating element which is immersed in water is substantially 100 percent efficient whereas gas water heater are much less efficient, usually in the range of from about 60 to 80 percent due to heat loss. Also, gas water heaters produce noise when the burner is operated as opposed to electric water heaters which do not produce noise when the elements are in use heating the water. Gas water heaters, however, heat water much more quickly than electric water heaters. It would be desirable to construct a water heater which overcomes the above mentioned disadvantages and which utilizes the advantages of both energy type water heaters. It would also be advantageous to utilise, in combination, a renewable energy source to reduce the demand on the electric grid or gas distribution network.
Electric utilities as well as gas utilities have a need to take control of water heaters to prevent excessive demand during peak hours and to use its electricity or gas when the demand and cost is low. Such control would create an equilibrium or a mean demand of electricity or gas. Control devices have been developed and continue to be developed to remotely control the demand for electricity or gas. It would therefore be desirable to construct a water heater which can be remotely controlled by a utility to shed load while at the same time does not deprive the consumer from having a continuous supply of hot water.